The accumulation and build-up of plaque or emboli within blood vessel walls presents a very serious problem to humans and other higher order primates. Problems arise in that plaque material attaches itself to the inner walls of blood vessels and begins a process of gradually building-up added plaque whereby the available flow passage within the artery is severely restricted and, if left untreated, leads to blockages of blood flow that lead to serious injury to portions of the heart and other portions of the vascular system. Such blocked or partially blocked arteries usually require serious surgical procedures such as bypass surgery and the like. While a variety of devices have been designed, they most typically comprise a cutting head supported by an elongated usually flexible catheter member which in turn is coupled to a drive mechanism that powers a cutting head inserted into a selected blocked artery via an incision in the outer body and manipulated so as to provide a path for moving the cutting head carefully into the affected area of plaque build-up. The cutting head works to sever the plaque emboli from the inner vessel wall and to loosen and crush it into a fine particle mixture for removal from the blood circulatory system into the liver for elimination. There are several problem areas in the procedure. For example, the use of a sharp cutting tool within the delicate arterial passages expose the patient to substantial risk from damage to the inner walls of the affected artery.
Further, the structures designed to avoid or minimize risk of damage to artery walls presented by the cutter generally rely on some sort of alignment apparatus which itself may tend to block the artery during the treatment which subjects the patient to further risk and potential injury.
The cutter heads of conventional catheters often do not pulverize the plaque debris. This unpulverized plaque debris may actually increase blood flow resistance inside the lumen of the catheter. This problem may persist despite the use of vacuum or negative pressure applied to the catheter from its downstream side. As a result, there arises an increased risk of debris lodging in a downstream segment of the blood vessel which in turn may cause an infarction or blockage.
Thus, while the ability to remove embolic plaque using an inserted cutting tool catheter presents hope for many afflicted individuals, there nonetheless remains a continuing need in the art for evermore effective, improved, less injurious, and safer cutting catheters.